commit 8b9a2cb68b290e550695124d7ef0511225b451d5 Author: Nick Mathewson nickm@torproject.org Date: Fri Sep 27 11:54:36 2013 -0400
Faster circuit_get_by_rend_token_and_purpose()
On busy servers, this function takes up something like 3-7% in different profiles, and gets invoked every time we need to participate as the midpoint in a hidden service.
So maybe walking through a linked list of all the circuits here wasn't a good idea. --- changes/bug9841 | 7 +++ src/or/circuitlist.c | 148 +++++++++++++++++++++++++++++++++++++++++++++----- src/or/circuitlist.h | 2 + src/or/or.h | 34 +++++++----- src/or/rendmid.c | 6 +- 5 files changed, 166 insertions(+), 31 deletions(-)
diff --git a/changes/bug9841 b/changes/bug9841 new file mode 100644 index 0000000..8b40dda0 --- /dev/null +++ b/changes/bug9841 @@ -0,0 +1,7 @@ + o Minor features (performance): + + - Faster server-side lookups of rendezvous and introduction point + circuits by using hashtables instead of linear searches over all + the circuits. These functions previously accounted between 3 and + 7% of CPU usage on some busy relays. + diff --git a/src/or/circuitlist.c b/src/or/circuitlist.c index b0e24a5..8ab673c 100644 --- a/src/or/circuitlist.c +++ b/src/or/circuitlist.c @@ -31,6 +31,7 @@ #include "rephist.h" #include "routerlist.h" #include "routerset.h" + #include "ht.h"
/********* START VARIABLES **********/ @@ -45,6 +46,9 @@ static void circuit_free(circuit_t *circ); static void circuit_free_cpath(crypt_path_t *cpath); static void circuit_free_cpath_node(crypt_path_t *victim); static void cpath_ref_decref(crypt_path_reference_t *cpath_ref); +//static void circuit_set_rend_token(or_circuit_t *circ, int is_rend_circ, +// const uint8_t *token); +static void circuit_clear_rend_token(or_circuit_t *circ);
/********* END VARIABLES ************/
@@ -672,6 +676,8 @@ circuit_free(circuit_t *circ) crypto_cipher_free(ocirc->n_crypto); crypto_digest_free(ocirc->n_digest);
+ circuit_clear_rend_token(ocirc); + if (ocirc->rend_splice) { or_circuit_t *other = ocirc->rend_splice; tor_assert(other->base_.magic == OR_CIRCUIT_MAGIC); @@ -1129,21 +1135,118 @@ circuit_get_next_by_pk_and_purpose(origin_circuit_t *start, return NULL; }
-/** Return the first OR circuit in the global list whose purpose is - * <b>purpose</b>, and whose rend_token is the <b>len</b>-byte - * <b>token</b>. */ +/** Map from rendezvous cookie to or_circuit_t */ +static digestmap_t *rend_cookie_map = NULL; + +/** Map from introduction point digest to or_circuit_t */ +static digestmap_t *intro_digest_map = NULL; + +/** Return the OR circuit whose purpose is <b>purpose</b>, and whose + * rend_token is the REND_TOKEN_LEN-byte <b>token</b>. If <b>is_rend_circ</b>, + * look for rendezvous point circuits; otherwise look for introduction point + * circuits. */ static or_circuit_t * -circuit_get_by_rend_token_and_purpose(uint8_t purpose, const char *token, - size_t len) +circuit_get_by_rend_token_and_purpose(uint8_t purpose, int is_rend_circ, + const char *token) { - circuit_t *circ; - for (circ = global_circuitlist; circ; circ = circ->next) { - if (! circ->marked_for_close && - circ->purpose == purpose && - tor_memeq(TO_OR_CIRCUIT(circ)->rend_token, token, len)) - return TO_OR_CIRCUIT(circ); + or_circuit_t *circ; + digestmap_t *map = is_rend_circ ? rend_cookie_map : intro_digest_map; + + if (!map) + return NULL; + + circ = digestmap_get(map, token); + if (!circ || + circ->base_.purpose != purpose || + circ->base_.marked_for_close) + return NULL; + + if (!circ->rendinfo || + ! bool_eq(circ->rendinfo->is_rend_circ, is_rend_circ) || + tor_memneq(circ->rendinfo->rend_token, token, REND_TOKEN_LEN)) { + char *t = tor_strdup(hex_str(token, REND_TOKEN_LEN)); + log_warn(LD_BUG, "Wanted a circuit with %s:%d, but lookup returned %s:%d", + safe_str(t), is_rend_circ, + safe_str(hex_str(circ->rendinfo->rend_token, REND_TOKEN_LEN)), + (int)circ->rendinfo->is_rend_circ); + tor_free(t); + return NULL; } - return NULL; + + return circ; +} + +/** Clear the rendezvous cookie or introduction point key digest that's + * configured on <b>circ</b>, if any, and remove it from any such maps. */ +static void +circuit_clear_rend_token(or_circuit_t *circ) +{ + or_circuit_t *found_circ; + digestmap_t *map; + + if (!circ || !circ->rendinfo) + return; + + map = circ->rendinfo->is_rend_circ ? rend_cookie_map : intro_digest_map; + + if (!map) { + log_warn(LD_BUG, "Tried to clear rend token on circuit, but found no map"); + return; + } + + found_circ = digestmap_get(map, circ->rendinfo->rend_token); + if (found_circ == circ) { + /* Great, this is the right one. */ + digestmap_remove(map, circ->rendinfo->rend_token); + } else if (found_circ) { + log_warn(LD_BUG, "Tried to clear rend token on circuit, but " + "it was already replaced in the map."); + } else { + log_warn(LD_BUG, "Tried to clear rend token on circuit, but " + "it not in the map at all."); + } + + tor_free(circ->rendinfo); /* Sets it to NULL too */ +} + +/** Set the rendezvous cookie (if is_rend_circ), or the introduction point + * digest (if ! is_rend_circ) of <b>circ</b> to the REND_TOKEN_LEN-byte value + * in <b>token</b>, and add it to the appropriate map. If it previously had a + * token, clear it. If another circuit previously had the same + * cookie/intro-digest, mark that circuit and remove it from the map. */ +static void +circuit_set_rend_token(or_circuit_t *circ, int is_rend_circ, + const uint8_t *token) +{ + digestmap_t **map_p, *map; + or_circuit_t *found_circ; + + /* Find the right map, creating it as needed */ + map_p = is_rend_circ ? &rend_cookie_map : &intro_digest_map; + + if (!*map_p) + *map_p = digestmap_new(); + + map = *map_p; + + /* If this circuit already has a token, we need to remove that. */ + if (circ->rendinfo) + circuit_clear_rend_token(circ); + + found_circ = digestmap_get(map, (const char *)token); + if (found_circ) { + tor_assert(found_circ != circ); + circuit_clear_rend_token(found_circ); + if (! found_circ->base_.marked_for_close) + circuit_mark_for_close(TO_CIRCUIT(found_circ), END_CIRC_REASON_FINISHED); + } + + /* Now set up the rendinfo */ + circ->rendinfo = tor_malloc(sizeof(*circ->rendinfo)); + memcpy(circ->rendinfo->rend_token, token, REND_TOKEN_LEN); + circ->rendinfo->is_rend_circ = is_rend_circ ? 1 : 0; + + digestmap_set(map, (const char *)token, circ); }
/** Return the circuit waiting for a rendezvous with the provided cookie. @@ -1154,7 +1257,7 @@ circuit_get_rendezvous(const char *cookie) { return circuit_get_by_rend_token_and_purpose( CIRCUIT_PURPOSE_REND_POINT_WAITING, - cookie, REND_COOKIE_LEN); + 1, cookie); }
/** Return the circuit waiting for intro cells of the given digest. @@ -1164,8 +1267,23 @@ or_circuit_t * circuit_get_intro_point(const char *digest) { return circuit_get_by_rend_token_and_purpose( - CIRCUIT_PURPOSE_INTRO_POINT, digest, - DIGEST_LEN); + CIRCUIT_PURPOSE_INTRO_POINT, 0, digest); +} + +/** Set the rendezvous cookie of <b>circ</b> to <b>cookie</b>. If another + * circuit previously had that cookie, mark it. */ +void +circuit_set_rendezvous_cookie(or_circuit_t *circ, const uint8_t *cookie) +{ + circuit_set_rend_token(circ, 1, cookie); +} + +/** Set the intro point key digest of <b>circ</b> to <b>cookie</b>. If another + * circuit previously had that intro point digest, mark it. */ +void +circuit_set_intro_point_digest(or_circuit_t *circ, const uint8_t *digest) +{ + circuit_set_rend_token(circ, 0, digest); }
/** Return a circuit that is open, is CIRCUIT_PURPOSE_C_GENERAL, diff --git a/src/or/circuitlist.h b/src/or/circuitlist.h index 874f68c..d8c107f 100644 --- a/src/or/circuitlist.h +++ b/src/or/circuitlist.h @@ -43,6 +43,8 @@ origin_circuit_t *circuit_get_next_by_pk_and_purpose(origin_circuit_t *start, const char *digest, uint8_t purpose); or_circuit_t *circuit_get_rendezvous(const char *cookie); or_circuit_t *circuit_get_intro_point(const char *digest); +void circuit_set_rendezvous_cookie(or_circuit_t *circ, const uint8_t *cookie); +void circuit_set_intro_point_digest(or_circuit_t *circ, const uint8_t *digest); origin_circuit_t *circuit_find_to_cannibalize(uint8_t purpose, extend_info_t *info, int flags); void circuit_mark_all_unused_circs(void); diff --git a/src/or/or.h b/src/or/or.h index 5318b0f..510b8ea 100644 --- a/src/or/or.h +++ b/src/or/or.h @@ -99,6 +99,7 @@ #include "ht.h" #include "replaycache.h" #include "crypto_curve25519.h" +#include "tor_queue.h"
/* These signals are defined to help handle_control_signal work. */ @@ -3152,20 +3153,8 @@ typedef struct or_circuit_t { * is not marked for close. */ struct or_circuit_t *rend_splice;
-#if REND_COOKIE_LEN >= DIGEST_LEN -#define REND_TOKEN_LEN REND_COOKIE_LEN -#else -#define REND_TOKEN_LEN DIGEST_LEN -#endif + struct or_circuit_rendinfo_s *rendinfo;
- /** A hash of location-hidden service's PK if purpose is INTRO_POINT, or a - * rendezvous cookie if purpose is REND_POINT_WAITING. Filled with zeroes - * otherwise. - * ???? move to a subtype or adjunct structure? Wastes 20 bytes. -NM - */ - char rend_token[REND_TOKEN_LEN]; - - /* ???? move to a subtype or adjunct structure? Wastes 20 bytes -NM */ /** Stores KH for the handshake. */ char rend_circ_nonce[DIGEST_LEN];/* KH in tor-spec.txt */
@@ -3186,6 +3175,25 @@ typedef struct or_circuit_t { uint64_t total_cell_waiting_time; } or_circuit_t;
+typedef struct or_circuit_rendinfo_s { + +#if REND_COOKIE_LEN != DIGEST_LEN +#error "The REND_TOKEN_LEN macro assumes REND_COOKIE_LEN == DIGEST_LEN" +#endif +#define REND_TOKEN_LEN DIGEST_LEN + + /** A hash of location-hidden service's PK if purpose is INTRO_POINT, or a + * rendezvous cookie if purpose is REND_POINT_WAITING. Filled with zeroes + * otherwise. + */ + char rend_token[REND_TOKEN_LEN]; + + /** True if this is a rendezvous point circuit; false if this is an + * introduction point. */ + unsigned is_rend_circ; + +} or_circuit_rendinfo_t; + /** Convert a circuit subtype to a circuit_t. */ #define TO_CIRCUIT(x) (&((x)->base_))
diff --git a/src/or/rendmid.c b/src/or/rendmid.c index 1bd11f6..8090bf2 100644 --- a/src/or/rendmid.c +++ b/src/or/rendmid.c @@ -111,7 +111,7 @@ rend_mid_establish_intro(or_circuit_t *circ, const uint8_t *request,
/* Now, set up this circuit. */ circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_INTRO_POINT); - memcpy(circ->rend_token, pk_digest, DIGEST_LEN); + circuit_set_intro_point_digest(circ, (uint8_t *)pk_digest);
log_info(LD_REND, "Established introduction point on circuit %u for service %s", @@ -251,7 +251,7 @@ rend_mid_establish_rendezvous(or_circuit_t *circ, const uint8_t *request, }
circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_REND_POINT_WAITING); - memcpy(circ->rend_token, request, REND_COOKIE_LEN); + circuit_set_rendezvous_cookie(circ, request);
base16_encode(hexid,9,(char*)request,4);
@@ -327,7 +327,7 @@ rend_mid_rendezvous(or_circuit_t *circ, const uint8_t *request, circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_REND_ESTABLISHED); circuit_change_purpose(TO_CIRCUIT(rend_circ), CIRCUIT_PURPOSE_REND_ESTABLISHED); - memset(circ->rend_token, 0, REND_COOKIE_LEN); + circuit_set_rendezvous_cookie(circ, NULL);
rend_circ->rend_splice = circ; circ->rend_splice = rend_circ;